N-(2&#39;,5&#39;-dihydroxyphenyl or 2&#39;,5&#39;-dilower-alkoxyphenyl) alkylene pyridinium compounds and derivatives thereof

ABSTRACT

QUATERNARY AMMONIUM COMPOUNDS OF THE FORMULA   DEV-LINK-QUAT   WHEREIN DEV IS A DEHYDROXYARYL SILVER HALIDE DEVELOPING RADICAL OR A DIALKYOXYARYL OR DIALKOXYMETHOXYARYL PRECURSOR THEREOF; LINK IS A HYDROCARBON RADICAL OF AT LEAST TWO AND PREFERABLY THREE CARBON ATOMS OR A HYDROCARBON RADICAL PRECEDED BY AND/OR INTERRUPED BY INDIVIDUAL ATOMS OF OXYGEN OR SULFUR WITH THE PROVISO THAT AN INTERRUPING ATOM OF OXYGEN OR SULFUR CANNOT BE CLOSER THAN TWO CARBON ATOMS AWAY IN THE CHAIN FROM THE POSITIVELY CHARGED NITROGEN ATOMS OF THE QUARTERNARY AMMONNIUM RADICAL QUAT BONDED TO LINK THROUGH THE PENETAVALENT NITROGEN ATOMS. THE PREFERRED MODE OF PREPARATION OF THESE COMPOUNDS IS BY THE ALKYLATION OF AN AMINE. THESE COMPOUNDS ARE ESPECIALLY USEFUL IN PHOTOGRAPHY AS SILVER HALIDE DEVELOPING AGENTS.

United States Patent M 3,799,937 N-(2', -DIHYDROXYPHENYL 0R 2',5'-DILOWER- ALKOXYPHENYL)ALKYLENE PYRIDINIUM COMPOUNDS AND DERIVATIVES THEREOF Stanley M. Bloom, 89 Gordon Road, Waban, Mass. 02155 No Drawing. Original application July 1, 1968, Ser. No. 741,293, now Patent No. 3,590,692, dated July 6, 1971. Divided and this 'application Dec. 30, 1970, Ser.

Int. Cl. C07d 31/28 US. Cl. 260-297 R 6 Claims ABSTRACT OF THE DISCLOSURE Quaternary ammonium compounds of the formula: DEVLINKQUAT wherein DEV is a dihydroxyaryl silver halide developing radical or a dialkoxyaryl or dialkoxymethoxyaryl precursor thereof; LINK is a hydrocarbon radical of at least two and preferably three carbon atoms or a hydrocarbon radical preceded by and/or interrupted by individual atoms of oxygen or sulfur with the proviso that an interrupting atom of oxygen or sulfur cannot be closer than two carbon atoms away in the chain from the positively charged nitrogen atom of the quarternary ammonium radical QUAT bonded to LINK through the penetavalent nitrogen atom.

The preferred mode of preparation of these compounds is by the alkylation of an amine. These compounds are especially useful in photography as silver halide developing agents.

This application is a division of US. patent application Ser. No. 741,293 filed July 1, 1968, now US. Pat. No. 3,590,692 dated July 6, 1971.

This invention relates to photography and, more particularly, to novel silver halide developing agents.

Mees, in The Theory of the Photographic Process, revised edition, copyright 1954, at page 556, indicates that Kumetat in Zeitschrift fiir wissenachaftliche Photographic, volume 43, p. 113 et seq, 1948, states that hydroquinone derivatives in which one hydrogen atom of an aromatic ring is substituted by a pyridinium ring, e.g.,

are good silver halide developing agents. The introduction of positive substituents such as CH and -OCH onto the hydroquinone nucleus of such derivatives increases the development capability of such compounds whereas the introduction of negative substituents decreases it. The positive charge of the pyridinium group might be expected to weaken the developing agent by the withdrawal of electrons from the hydroquinone system. The positive charge on the pyridinium group would be expected to make it easier for the hydroquinone ion to penetrate the negative charge barrier surrounding the silver halide grains, and this action may more than offset the electron withdrawal effect.

When such developing agents were utilized in diffusion transfer processing compositions which, as is known in the art, have a high pH of about 13, it was found that the developing agent fragmented. It has now been found that if a linking group containing at least two and preferably three carbon atoms is present between the positively charged nitrogen atom and the hydroquinone radical, or at least two carbon atoms between the positively charged nitrogen atom and any other atoms, such as oxygen or sulfur atoms, comprising a part of said linking group that such fragmentation will not occur. The utilization of the linking group also overcomes any electron withdrawing elfect attributed to the quaternary nitrogen atom while still maintaining the benefits to be derived from the positive charge in regard to the penetration of the negative charge barrier.

Accordingly, it is one object of the present invention to provide novel quaternary ammonium compounds which are alkali stable silver halide developing agents suitable for use in diffusion transfer processes.

Another object is to provide novel processes and processing compositions for forming images by a diffusion transfer process wherein the novel compounds are utilized as the silver halide developing agent.

Still another object is to provide procedures for the preparation of the novel compounds.

Other objects of this invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.

The novel compounds of this invention may be represented by the formula:

wherein DEV is a dihydroxyaryl silver halide developing radical; or a dialkoxyaryl or dialkoxymethoxy precursor thereof, or a monoamine monohydroxy silver halide developing radical; or a nitroalkoxyaryl of nitroalkoxymethoxyaryl precursor thereof; LINK is a divalent organic radical bonded to a nuclear carbon atom of DEV and to QUAT through a pentavalent nitrogen atom of QUAT, wherein the atom of LINK next adjacent to DEV is selected from among oxygen, sulfur and carbon, the remainder of said radical being a linear 2 to 9 carbon atom hydrocarbon chain or a hydrocarbon chain which is interrupted by individual oxygen or sulfur atoms, with the proviso that an interrupting atom of oxygen or sulfur is not bonded to the carbon atom of LINK bonded to said pentavalent nitrogen atom of QUAT, and QUAT is a cyclic or acyclic quaternary ammonium radical which is bonded through the pentavalent nitrogen atom thereof to LINK and which radical when acyclic has three of its valences filled by three unsubstituted or halogen substituted hydrocarbon groups, and which radical when entirely cyclic comprises a heterocyclic ring which fills three of its valences, and which radical when partially cyclic and partially acyclic, contains an acyclic unsubstituted or halogen substituted hydrocarbon group to fill one valence, two other valencies being filled by a heterocyclic ring, said n'ngs containing in addition to the nitrogen atom bonded to the -LINK- radical, carbon atoms, hydrogen atoms and optionally an atom selected from the group consisting of nitrogen, oxygen, selenium and sulfur.

As noted above, it has unexpectedly been discovered that these dihydroxyaryl containing developing agents are stable in high concentrations of alkali and as such can be utilized in diffusion transfer processing compositions, which as is known in the art, are generally of the pH DEVLINKQUAT of about 13 or more. This is surprising in view of the fact that compounds of the formula:

wherein DEV is a dihydroxyaryl silver halide developing radical; R R R R and R are hydrocarbon substituents and M comprises the atoms necessary to complete a heterocyclic ring, when placed in strongly alkaline media, liberate the pertinent amine compound. This liberation is easily attested to as, for instance, by the smell of pyridine being liberated from an alkaline solution of the compound:

The novel compounds of this invention for ease and simplicity may be represented by the formula:

e is 1 or 0; R is a divalent radical of the formula:

wherein m is a number from 0 to 4 inclusive; n is a number from 0 to 8 inclusive; the sum of m+n being not greater than 8;

D is a cyclic, acyclic, or part cyclic part acyclic quaternary ammonium radical selected from the group of radicals of the formulae:

wherein each Q and T are acyclic hydrocarbon or halogen substituted hydrocarbon groups, M represents the atoms necessary to complete a heterocyclic ring and contains in addition to carbon and hydrogen atoms, optionally an atom selected from the group consisting of nitrogen, oxygen, sulfur and selenium, and X is an anion whose presence is necessary to balance the positive charge of the pentavalent nitrogen.

As has been indicated, the compounds of this invention are within the formula:

L, as has been indicated is an ortho or para dihydroxy bisalkoxy or bisalkoxymethoxyaryl radical.

As examples of useful dihydroxyphenyl radicals comprising L substituents, mention may be made of orthodihydroxyphenyl, para-dihydroxyphenyl and nuclear-substituted derivatives thereof, e.g., chloro, methyl, phenyl, and/or methoxy-substituted derivatives thereof, particularly nuclear-substituted p-dihydroxyphenyl such as methylhydroquinonyl, p-methylphenylhydroquinonyl, chlorohydroquinonyl, methoxyhydroquinonyl, 2,6-dimethylhydroquinonyl, 2,6-dimethoxyhydroquinonyl, 2-methoxy-6- methylhydroquinonyl, 2,3-dimethylhydroquinonyl, 2,5,6,- trimethylhydroquinonyl, etc.

As examples of useful dihydroxynaphthyl silver halide developing radicals comprising L mention may be made of any of the above dihydroxyphenyl radicals wherein the benzene ring is replaced by a naphthalene ring and the other substituents are appropriately situated.

As examples of useful dialkoxyaryl and dialkoxymethoxyaryl radicals for this invention, mention may be made of the above dihydroxyphenyl radicals wherein the hydroxyl groups are replaced by alkoxy groups containing from 1 to 5 carbon atoms, and the aryl ring is either a benzene ring or a naphthalene ring.

As examples of useful nitrogen containing silver halide developing radicals, mention can be made of any of the above-mentioned dihydroxyaryl radicals wherein one of the hydroxyl groups is replaced by an -NH group. The precursors for such nitrogen containing developing radicals are those radicals which contain an NO* group ortho or para to the hydroxyl precursor group. As examples of such nitroalkoxyaryl and nitroalkoxymethoxyaryl radicals, mention may be made of 2 nitro, 5 ethoxy benzene and any of the dihydroxyaryl radicals above wherein one hydroxyl group is replaced by a nitro group and the other hydroxyl group is replaced by an alkoxy or alkoxymethoxy group.

A previously defined, taken together with R comprise the total linking unit between the silver halide developing radical and the quaternary ammonium radical, D.

As illustrations of suitable alkylene radicals comprehended by R, mention may be made of radicals such as As examples of some hydrocarbon substituents containing unsaturation that are suitable as R radicals mention can be made of radicals such as As examples of R radicals containing ether and thioether linkages, mention can be made of CH O-CH CH -CH -CH --S-CH CH -S-CH -CH and OH OCH -CH CH 'CH2CH2 CHz-CHg-- It should be noted that any R substituent that comprises purely hydrocarbon units must contain at least'2 and preferably 3 carbon atoms in the chain to avoid cleavage of the molecule when it is placed in a strongly alkaline environment. If oxygen or sulfur atoms are present in the chain, there should not be an atom of one of these bonded to the same carbon atom as is bonded to the pentavalent nitrogen atom of D, nor should such an atom be bonded directly to the pentavalent nitrogen atom of D. Here too, the necessity for 2 carbon atoms between such oxygen or sulfur atoms is to avoid cleavage in an alkaline medium.

D is a quaternary ammonium radical. As is known, quaternary ammonium compounds are organic compounds containing a pentavalent nitrogen atom. Generally they can be considered as derivatives of ammonium compounds wherein the four valences usually occupied by the hydrogen atoms are occupied by organic radicals. Generally the organic radicals are joined directly to the pentavalent nitrogen through a single or double carbon-to-nitrogen bond. The term quaternary ammonium, as used herein, is intended to cover compounds wherein the pentavalent nitrogen is one of the nuclear atoms in a heterocyclic ring as well as those wherein each of the four valences is attached to separate organic radicals. Note the formulae above.

Typical quaternary ammonium radicals include 2- picolinium-p-toluenesulfonate, pyridinium 'bromide, triethylamine chloride, 3-quinolinium bromide, n-methyl piperidinium iodide, tri-omega chlorobutylamine methyl sulfonate, etc.

While the preferred quaternary ammonium radicals are those where Q, T and M are all hydrocarbon, it is understood as set forth above that these Q, T and M groups can contain other hetero atoms. As such, typical cyclic quaternary ammonium radicals suitable for use in this invention would include those derived from. compounds of the thiazole, selenazole, oxazole, imidazole and indole series among others.

In a preferred embodiment of this invention, L. is a dihydroxyphenyl radical, A-R is an alkylene radical of 2 to 10 carbon atoms inclusive, and D is a quaternary ammonium radical. Such compounds are represented by the formulae:

(4) OH I E ][CH2] r'QUAT; HO-

wherein z is an integer of from 2 to 10 inclusive.

Another preferred embodiment comprises compounds wherein L is a bisdialkoxyphenyl radical, A-R and D are of the significance indicated at Formula 5. Such compounds are represented by the formulae:

Q OH F UAT; mambo l flv wherein z is an integer of from 2 to 10 inclusive, and y is an integer of from 1 to 5 inclusive.

In the scope of Formulae (4) and (5), typical preferred compounds include N-' (2',5-dihydroxypheny1) propyl 3 pyridinium bromide, N-'y(2',5'-dihydroxyphenyl) propyl-4-methylquinolinium bromide and N-v (2,5'-dimethoxyphenyl)butyl-pyridinium tosylate, which are of the formulae:

Other compounds within the scope of this invention include:

(9) ocrnocm i CH3 SCHzCH:CH:N OHa 01- omocm (10) oornoom cmcm o-cHr-cHr-cm-fi-cmom Br CHZCH! (LCHaOCH;

/CH2-CHz--CH3 H0 cHr-cm-cm-oHr-fi-om-om Br CH2CH2CH;

01 cnt-o-om-cnrif one-so.-

(13) on nocm-s-om-cm-s-om-cm-iqj Br ocmocm o-om-om-o-oHi-cm-o-cm-om-om- CH: CHzOCHa mo-Qsor 15 on on,

OH CH:

+i/ -s-om-omo-om-omo-om-cm-N or- In general, the novel compounds of this invention can he prepared by several methods. One such method comprises reacting a tertiary amine, such as pyridine, with a halogen substituted alkyl acetal, such as a. compound of the formula:

( 7) CHaBr CH H50 \OCHI wherein y is an integer of from 1 to 5 inclusive.

This intermediate product is reacted with hydrogen ion, such that the aldehyde derivative is prepared. This aldehyde compound is reacted in base with an acetophenone such as the compound of the formula:

(ll-CH O CHI to give rise to a product of the formula:

H H -o-o=coH21,oH,i-1 ll 0 I O CH:

which can then be reduced, such as by hydrogen, to a dialkoxyphenyl quaternary ammonium compound,

Subsequent treatment of the alkoxy groups with a dealkylating agent gives rise to the hydroxyl derivative of the alkoxy compound, if such is desired. Details on this step will be set forth further on in the specification.

The preferred means of preparing compounds of the present invention which do not contain the optional A group, i.e., oxygen or sulfur, and which have an all bydrocarbon R, is by the alkylation of a tertiary amine, in the absence of heat, so as to avoid side reactions. This reaction can be illustrated as follows, a compound of the formula:

( Ki mywherein y and z are as previously defined, and X is haloor OH -SO or its ortho dialkoxy equivalent, is reacted with a tertiary amine, as for instance a compound and a product of the formula:

( His gonna-i6!) X- is obtained. Dealkylation of the alkoxy groups prepares the dihydroxy compound, if such is desired.

Compounds containing the optional A group, namely an atom of oxygen or sulfur, and an all hydrocarbon R, are prepared by a slightly diiferent alkylation process. This is necessary in view of the fact that the dihydroxy compounds cannot be prepared by the aforementioned synthesis in view of the inability of any reagent to differentiate between the alkoxy groups in the 2,5 positions and the alkoxy group that would be in the 1 position. Therefore, to prepare compounds containing the optional A, group, an alkoxyalkoxy compound such as the one of the formula:

mouth-o (24) (!)CI'I O[ HJ]yH -A[CH;].OH

OCH;0[CH],H

or its ortho equivalent, wherein A, y and z are as previously defined, is reacted with a compound such as toluene sulfonyl chloride in an organic base such as pyridine to prepare an intermediate of the formula:

25 OCHgO[C I]yH oomorcmlyn which is then reacted with any tertiary amine, such as triethyl amine to yield an end product of the formula:

Treatment of the above with dilute mineral acid removes the alkoxymethyl groups and prepares the dihydroxy product.

9 Compounds containing ether or thioether groups in the R unit of LA -RD are prepared by treating compounds of the following formulae:

y and A are as previously defined, or their ortho equivalents with a reagent such as NaH in dimethylsulfoxide followed by the addition of one mole of ethylene oxide or its sulfur counterpart. More than one ether or thioether units can be added to increase the size of R by increasing the number of moles of ethylene oxide or ethylene sulfide added in the addition step. The preferred mode, however, is the unimolar addition followed by a NaH treatment between the additions of each mole of ethylene oxide or sulfide. Following the addition of the ether units to the starting materials, the same alkylation processes are carried out as well as same treatment to remove the alkoxymethyl groups. It is, of course, understood that other epoxide units such as propylene oxide, etc., can be added in like manner.

The removal of the protective alkoxy groups to form the desired hydroxy-substituted compounds may be accomplished by known hydrolysis techniques. A typical dealkylation process involves complexing the group to be removed with boron tribromide, followed by decomposition of the resulting complex with water. Another dealkylation process comprises treatment of the methoxy intermediate with aqueous HBr or HBr in acetic acid.

The various reaction conditions, e.g., time, temperature, pressure, selection of solvents to form the reaction mixture, etc., are not critical to the practice of this invention unless so indicated with the confines of this application, and will therefore be readily apparent to the skilled artisan in the light of the foregoing descriptive material. The essence of the invention is, therefore, the aforementioned selection of steps, in the order described to obtain the desired end product, as well as the end product itself.

The invention will be illustrated in greater detail in conjunction with the following specific examples which set out representative preparations of the novel compounds of this invention, which, however, are not limited to the details therein set forth and are intended to be illustrative only.

EXAMPLE I Preparation of N-'y(2',5'-dihydroxyphenyl) propyl pyridinium bromide In a nitrogen atmosphere, 15 g. of lithium aluminum hydride (M.W. 37.95), 0.4 mole, was slurried in 200 cc. of dry ether. 87 g. of 2,S-dimethoxydihydrocinamic acid, 0.416 mole, in 550 cc. of dry ether was added dropwise. The addition of the ether caused the dihydrocinnamic acid to reflux without the addition of extra heat. Stirring was continued for a period of one hour. Sufiicient water was added dropwise, to decompose excess lithium aluminum hydride.

620 cc. of 10% H S were added to the reaction ves' sel. A two layer system resulted. The ether layer was separated and washed several times with an aqueous solution of NaHCO cautiously, and then with water and dried. The ether was evaporated off leaving a fluid oil comprising 2,5-dimethoxyphenyl propyl alcohol. 54 g. of the approximately 70 g. of said alcohol were cooled to -10 C. To this was added 40 g. of PBr 0.14 mole dropwise. The temperature was permitted to reach room temperature and the mixture was stirred for 2 hours and then allowed to stand overnight. It was heated to C. for 0.5 hour and then cooled and poured onto ice mixed with water. The end product which was 2,5'-dimethoxyphenyl 3-propyl bromide was extracted with ether, washed and dried. 52 g. (0.2 mole) of the bromide and 15.8 g. (0.2 mole) of pyridine in 200 cc. of dioxane were heated for 52 hours, with two layers being formed. The desired product, a yellow viscous oil, was separated and then refluxed overnight in approximately 350 cc. of 48% HBr, while under nitrogen. The nitrogen blanket was maintained until most of the liquid evaporated. The remainder was cooled and acetone was added. The resulting precipitate was washed in acetone, collected and dried under vacuum. Approximately 16 g. of an orange-tan product was obtained. The product was recrystallized from ethanol, melting point 167 C. for analysis. The analysis was in agreement with the assignment of the structure as N-'y(2',5'-dlhydroxyphenyl)propyl pyridinium bromide.

Analysis-For C H NO B,: Calculated: Nitrogen, 4.52% Found: Nitrogen, 4.52%.

EXAMPLE II Preparation of N-v(2,5'-dihydroxyphenyl) propyl-4- methylquinolinium bromide 3-(2',5-dimethoxyphenyl)propanol, 34.0 g., 0.2 mole, was dissolved in 400 ml. of ethanol. Sodium borohydride, 7.4 g., 0.2 mole, was added and the reaction mixture refluxed two hours. The solvent was removed in vacuo and water and ethyl ether were added. The ether extract was washed with water, dried (anhydrous magnesium sulfate) and concentrated to a heavy oil. The oil, 27 g., 79%, 3-(2,5'-dimethoxyphenyl)propanol was used directly. An infrared analysis showed that no aldehyde remained unreacted.

The 3-(2',5'-dimethoxyphenyl)propanol, 27 g., 0.137 mole, was cooled to l0 and phosphorous tribromide 20 g., 0.074 mole, was added dropwise with stirring. The reaction was allowed to rise to room temperature and was stirred for an additional two hours and finally heated at 80 for /2 hour. The reaction mixture was poured into ice water and the product extracted into ethyl ether. The ether was washed with water and dried. The crude 3-(2', 5-dimethoxyphenyl)propyl bromide was obtained by removal of the ether.

Attempts to purify a sample of the crude product by distillation at 18 mm. pressure and a temperature of C. gave a clear liquid which was largely converted to a methoxy chroman. Because of this sensitivity to heat, the crude product was used directly in the synthesis of the quaternary salt.

The propyl bromide product, 5.6 g., 0.04 mole, and 4-methylquinoline, 5.6 g., 0.04 mole, were dissolved in 40 ml. dioxane and heated on the steam cone two days. On cooling, two layers were obtained. The dioxane layer was decanted and ethyl ether-ethyl acetate trituration was used to obtain the product. The crude solid was taken up in 60 ml. of concentrated hydrobromic acid and the reaction mixture refluxed 2 hours. The HBr was removed by evaporation on the steam cone using a nitrogen stream. Trituration of the residue with acetone gave 2 g. of N-y (2,5-dihydroxyphenyl)propyl 4" methylquinolinium bromide which was crystallized from ethanol M.P. 238-9 The photographic utilizaton of the novel compounds of this invention will be illustrated in greater detail in conjunction with the following specific examples which set forth representative processes and which are not intended to be limiting, but are meant to be illustrative only.

1 1 EXAMPLE III A photosensitive element was prepared by coating a gelatin subcoated film base at a speed of 15 feet per minute with a solution comprising 2 g. of a compound of the formula:

Ha Oh Water cc 100 NaOH g Hydroxyethyl cellulose g 3.9 Benzotriazole g 1 After an imibibition period of approximately one minute, the spreader element was separated and it was found that a good negative image was present in the photosensitive element.

In the following example, the novel compounds of this invention are utilized in a diffusion transfer process wherein unreduced (i.e., the hydroquinone form) quaternary ammonium developing agent is transferred by imbibition to an image-receiving layer and upon aerial oxidation, e.g., by oxygen in the air upon separation of the image-receiving layer from the photosensitive element, is caused to undergo an oxidative coupling with a second molecule of the quaternary ammonium developing agent.

dated Nov. 30, 1970, filed concurrently herewith. It is to be understood that not all compounds of the formula DEV'LINKQUAT are capable of participating in an oxidative reaction of this nature. Only the compounds which are capable of generating an enamine can so participate and then only if the pH has been adjusted to facilitate the self coupling reaction.

EXAMPLE IV A photosensitive element was prepared by coating a gelatin subcoated film base at a speed of 10 feet per mlnute with a solution comprising 1 g. of a compound of the formula:

which was dissolved in 100 cc. of a solution containing 5.0 g. cellulose acetate hydrogen phthalate in a 1:1 mixture, by volume, of methoxyethanol and ethanol. After this coating dried, a blue-sensitive silver iodobromide emulsion was coated thereupon at a speed of 10 feet per minute and allowed to dry. This photosensitive element was exposed and processed by spreading an aqueous processing composition between the thus exposed photosensitive element and a superposed image-receiving element, said aqueous processing composition comprising:

Water cc..- 100 NaOH g.. 5 Hydroxyethyl cellulose g 3.9 Benzotriazole g 2 4-methyl-phenyl hydroquinone g 0.1

The image-receiving element comprised a 2:1 mixture, by Weight, of gelatin and poly-4-vinyl pyridine containing a small amount of 1-phenyl-5-mercaptotetrazole coated upon a pigmented plastic base. After an imbibition period of approximately one minute, the image-receiving element was separated and contained a dense blue-positive transfer image.

EXAMPLE V Utilizing a pair of standard iodobromide panchromatic sensitized negatives, the compound was tested as a developing agent against 4-methy1phenylhydroquinone, a control developing agent whose developing characteristics are Well-known in a diffusion transfer process.

The processing compositions utilized comprised 100 cc. of water to which was added 3.8 g. of hydroxyethyl cellulose, 11.2 g. of pure KOH, 0.93 g. of the test compound and 0.6 g. of 4-methylphenyl hydroquinone, respectively. In duplicate tests, the negatives are exposed under conditions so that one-half of each negative is totally unexposed and the other half of the negative is totally exposed. The thus exposed negative and an imagereceiving element are brought into superposed relationship and the processing composition is spread therebetween as the exposed negative and the image-receiving element are advanced at a constant rate between a pair of rollers. The resulting sandwich is scanned by infrared light. All the components of the sandwich are transparent to infrared light except for silver formed by development. It 1s to be noted that no silver is deposited on the receivmg layer by diffusion transfer since a silver solvent is not present in the processing compositions. The reduction in lnfrared transmission due to silver formation as a functron of imbibition time is reproduced electronically as a trace on a time and density grid on an oscilloscope tube, and the resulting oscilloscope tracing is photographed. The upper line in each such oscilloscope tracing represents the initiation of the development of exposed silver halide and the amount of silver developed in a given time m the fully exposed areas of the negative. The lower line represents the initiation of the development of unexposed silver halide in the totally unexposed areas of the negative and the amount of unexposed silver halide developed and therefore is a direct representation of the amount of fog development. The results of this test indicating the difference in fog buildup by the two developing agents are set forth graphically below:

It is seen that the test compound is a better discriminatory developer, i.e., the delta density difference between exposed and unexposed areas was greater with the test compound than with the 4'-methylphenyl hydroquinone.

The compounds of the present invention can also be utilized as mordanting developing agents in accordance with the concepts of the novel image forming process of Howard C. Haas, the subject matter of which is found in copending application Ser. No. 740,965, now abandoned, filed concurrently herewith. The following non-limiting example is incorporated herein from said copending application to illustrate the utilization of the compounds of the present invention as silver halide developing agents which will interact with gelatin when they are oxidized to form in the photosensitive emulsion an imagewise distribution of a mordant for a negatively charged dye, such as an acid dye. When such a dye is associated with the instant compounds, it is mordanted in place in the developed areas of the photosensitive emulsion where it is free to transfer from the undeveloped areas to form a transfer image.

EXAMPLE VI A photosensitive element was prepared as follows: 3.75 g. of CI. 15080 Direct Red 3, Benzo Brilliant Geranine B, of the formula:

N S;Na J'SmNa was dissolved in 45 cc. of water. This solution was emulsified by means of a high shear mechanical agitator, with an aqueous solution of 5 g. of gelatin, to obtain a uniformly blended mixture. 50 cc. of the resulting dye dispersion were mixed with 78 cc. of water and then coated upon a subcoated film base. After this coating dried, a blue-sensitive silver iodobromide emulsion was coated thereupon at a coverage of 317.9 mg. per square foot of silver and allowed to dry. This photosensitive element was exposed and processed by spreading, between the thus exposed photosensitive element and a superposed imagereceiving element, an aqueous processing composition comprising:

Water 90 NaOH 4 Hydroxyethyl cellulose 3 N-'y(2',5' dihydroxyphenyl) propyl-pyridinium bromide 3 silver halide developing agents in diffusion transfer processes, both dye and silver.

It will be apparent that the relative proportions of developing agents and other ingredients and materials illustrated in the above examples may be varied to suit the requirements of one skilled in the art. Thus, it is within the scope of this invention to substitute alkalies other than sodium hydroxide in the processing composition. Likewise, it is also contemplated that where desirable the processing or developing compositions may be modified by the inclusion of other common components of developer compositions such as restraiuers, preservatives, accelerators, etc. Where the processing compositions are to be employed in silver diffusion transfer processes, they may have incorporated in them as a further ingredient a silver halide solvent such as sodium thiosulfate. If the processing composition is to be applied to the emulsion by being spread thereon in a thin layer, it may also include a film-forming thickening agent such, for example, as a high molecular weight polymer, e.g., hydroxyethyl cellulose or sodium carboxymethyl cellulose. Thus, by adding sodium thiosulfate to the pertinent compositions, e.g., Example IH, illustrated above and using an image-receiving layer containing silver precipitating agents as is well known in the art, in conjunction with the photosensitive element, a silver transfer image may be obtained.

It will be apparent that, by appropriate selection of the support and coatings forming the image-receiving element from among suitable known opaque and transparent materials, it is possible to obtain either a positive reflection print or a positive transparency.

As examples of useful color image-receiving materials, mention may be made of nylon, e.g., N-methoxymethylpolyhexamethylene adipamide, polyvinyl alcohol, and gelatin, particularly polyvinyl alcohol or gelatin containing a dye mordant such as p0ly-4-vinylpyridine.

The utility of the compounds of this invention is by no means limited to diffusion transfer processes for they may be satisfactorily employed in conventional multistage multibath photographic processes in black-and-white or color photography. A typical developer composition would include in addition to a compound of this invention, ingredients as sodium hydroxide, sodium sulfite and potassium bromide. After development is completed, any unreacted developing agent is washed out of the photosensitive element preferably with an alkaline washing medium or other medium in which unreacted developing agent is soluble.

In the preceding portions of the specification, the expression color has been used. This expression is intended to include the use of a plurality of colors to obtain black.

Since certain changes may be made in the above products and processes and compositions without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A compound selected from those represented by the formulae:

and

wherein z is an integer of from 2 to 10 inclusive, A is sulfur or oxygen, D is pyridiniurn and and X is an anion.

2. A compound as defined in claim 1 wherein z is 3 and X is a halide ion.

16 3. A compound selected from those represented by and f 1 T the formulae: (I)CHZ O[CH,]YH

. A[CHz]|D X- H(CH2)y I 5 [CI-Iflr-D X ocm-owmlyrr wherein y is an integer of from 1 to 5 inclusive, 2 is an integer of from 2 to 10 inclusive, A is sulfur or oxygen, mCHDYO D is a pyridinium radical and X is an anion.

4. A compound as defined in claim 2 wherein y is 1, 2)y z is 3 and X is a halide ion.

I 5. N 'y(2',5 dihydroxyphenyl) propyl pyridinium zl: bromide.

6. N-'y(2',5' dimethoxyphenyl propyl pyridinium bromide.

References Cited :)y

Klingsberhg, Pyridine and its Derivatives, Part Two, Interscience Publishers, pp. 24 and QD 401 K5 C.2.

ALAN L. ROTMAN, Primary Examiner US. Cl. X.R.

PatentNo. 3,799,937 Dated March 26,1974

Inventor(s) Sta ley M- Bloom It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as'showu below:

Column 1, line 6, after the ihventor's address add assignor to Polaroid Corporation, Cambridge, Mass.

Signed and sealed this 22nd day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR.' C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM Po-1050 (10-69) 1 USCOMWDC wanna i us. sovnuiluv' mum. ornct nus o:u-.u4 

